The Agent Skills Directory

[EXTERNAL_DOWNLOADS]: The skill provides instructions to download the nylas-pp-cli binary using npx -y @mvanhorn/printing-press-library or go install github.com/mvanhorn/printing-press-library/.... These resources are hosted on NPM and GitHub within the vendor's own infrastructure.
[COMMAND_EXECUTION]: The skill's primary function is the execution of shell commands through the nylas-pp-cli tool to interact with Nylas data and perform administrative tasks.
[DATA_EXFILTRATION]: The CLI tool includes a --deliver webhook:<url> parameter that enables command results to be transmitted to arbitrary network endpoints. Additionally, the webhook-replay command allows re-firing delivery payloads to external URLs, and the feedback command supports remote transmission via the NYLAS_FEEDBACK_ENDPOINT environment variable.
[DYNAMIC_EXECUTION]: The sql command enables the agent to execute arbitrary SQL queries against the local SQLite database containing synchronized Nylas data, including messages and contact details.
[INDIRECT_PROMPT_INJECTION]: The skill exhibits an attack surface for indirect prompt injection:
Ingestion points: Untrusted data is ingested from external mailboxes (messages, threads, events) via the Nylas API into a local store.
Boundary markers: The skill does not implement specific delimiters or warnings to instruct the agent to ignore potentially malicious instructions embedded in the synced message content.
Capability inventory: The tool possesses capabilities for network transmission (webhook delivery), data querying (SQL), and outbound communication (sending emails).
Sanitization: No documented sanitization or filtering of the ingested content is performed before it is processed by the agent.

pp-nylas